tone

The shadow of a tree on the road is not only a visual phenomenon. It is also audible. The oak, the poplar, the nut tree have their own specific levels of sound. The tone of a plane tree is entered like a room. It indicates a certain order in space, zones of tension, and zones of free passage. The same is true of a wall or a whole landscape.

-- Jacques Lusseyran Blindness, A New Seeing of the World
Translated by Dorothea Winkler